Low dyno numbers?!?!
Thread Starter
Intermediate
Joined: Apr 2014
Posts: 45
Likes: 0
Low dyno numbers?!?!
I have an ls3 in my c5 corvette with about 2500miles now, I went to the dyno today for the first time and got an extremely low number of 408hp/398 tq wheel?!? Why?!?! Mods are:
Heads ported and milled 30
Comp cam custom grind
Dual valve springs, tsp pushrods, titanium retainers etc.
94mm throttle body with halltech cai, full 3" exhaust (catless long tubes/off road x/mufflers)
160 thermostat
Msd plug wires, catch can, tr6 plugs, tuned by cj tunes in mn
Afr was 11.9 through the whole pull
Am I wrong for expecting more out of a h/c/I/e/tune and Bolt on ls3?? Dyno was outside on a 43 degree day
Heads ported and milled 30
Comp cam custom grind
Dual valve springs, tsp pushrods, titanium retainers etc.
94mm throttle body with halltech cai, full 3" exhaust (catless long tubes/off road x/mufflers)
160 thermostat
Msd plug wires, catch can, tr6 plugs, tuned by cj tunes in mn
Afr was 11.9 through the whole pull
Am I wrong for expecting more out of a h/c/I/e/tune and Bolt on ls3?? Dyno was outside on a 43 degree day
Last edited by Ls3 adventures; Apr 5, 2014 at 08:25 PM.
Race Director
Joined: Jan 2005
Posts: 10,924
Likes: 851
From: Daytona Beach FL
I dunno?? 
Butt...with the typical 15% power loss between the back of the engine to the wheels (for a manual transmission; auto may even be more than that), 408 rwhp equals about 480 hp at the flywheel.
What's the LS3 stock? I think 430 hp.
So....you've got a 50 hp gain over stock - not bad!!
Bob
Butt...with the typical 15% power loss between the back of the engine to the wheels (for a manual transmission; auto may even be more than that), 408 rwhp equals about 480 hp at the flywheel.
What's the LS3 stock? I think 430 hp.
So....you've got a 50 hp gain over stock - not bad!!
Bob
Melting Slicks
Joined: Jul 2008
Posts: 2,151
Likes: 6
From: Oceanside Ca/ Tampa FL
What heads? Are they stock and ported?
What Cam are you running?
Intake Manifold?
Auto/Manual?
There are so many variables to figure out your issue or it could be just mismatched components i.e camshaft to big for what you have etc...
What Cam are you running?
Intake Manifold?
Auto/Manual?
There are so many variables to figure out your issue or it could be just mismatched components i.e camshaft to big for what you have etc...
Thread Starter
Intermediate
Joined: Apr 2014
Posts: 45
Likes: 0
They are stock ls3 heads ported, polished, and milled 30thousandths and I'm trying to contact the previous owner to find the cam specs all I know is that it's a custom grind comp cam, stock intake manifold, and it's a manual transmission car
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Melting Slicks
Joined: Jul 2008
Posts: 2,151
Likes: 6
From: Oceanside Ca/ Tampa FL
I would get the info from the original owner like you stated. Get some facts and evidence of the work that was supposedly done to the car. I agree, very low numbers and something isn't adding up. Jay
Le Mans Master
Joined: Dec 2005
Posts: 6,995
Likes: 1,680
From: Southeast TX
You're a good 100 hp shy of where you should be on your average Dynojet. Healthy cam with boltons on an LS3 will typically see upper 400s with a few touching 500. Your cam is plenty healthy. With ported heads, 500+. Ask the dyno operator where his machine stacks up with other dynos in the area. If he's been there a while, I can guarantee you that he knows. If his doesn't read absurdly low, you have more work to do.
Simple question, How is it running? If it's really down a hundred hp, it's probably running like ****.
Simple question, How is it running? If it's really down a hundred hp, it's probably running like ****.
Last edited by old motorhead; Apr 6, 2014 at 10:39 AM.
Drifting
Joined: Dec 2012
Posts: 1,717
Likes: 28
From: O'Fallon IL
The cam seems quite aggressive and with 30 milled from the heads ill think the valves clearance is tight. Are the pistons notched? The afr can be leaned out some to about 12.2. What's the timing? These engine work well with 23-24* at wot.
At the end they're just numbers. Take it to the track and see how it performs. Specially the mph at the stripe.
At the end they're just numbers. Take it to the track and see how it performs. Specially the mph at the stripe.
Thread Starter
Intermediate
Joined: Apr 2014
Posts: 45
Likes: 0
You're a good 100 hp shy of where you should be on your average Dynojet. Healthy cam with boltons on an LS3 will typically see upper 400s with a few touching 500. Your cam is plenty healthy. With ported heads, 500+. Ask the dyno operator where his machine stacks up with other dynos in the area. If he's been there a while, I can guarantee you that he knows. If his doesn't read absurdly low, you have more work to do.
Simple question, How is it running? If it's really down a hundred hp, it's probably running like ****.
Simple question, How is it running? If it's really down a hundred hp, it's probably running like ****.
Race Director
Joined: Sep 2007
Posts: 16,557
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From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
The ultimate test of power is at the track. It's also a test of skill to put that power to use.
Thread Starter
Intermediate
Joined: Apr 2014
Posts: 45
Likes: 0
The cam seems quite aggressive and with 30 milled from the heads ill think the valves clearance is tight. Are the pistons notched? The afr can be leaned out some to about 12.2. What's the timing? These engine work well with 23-24* at wot.
At the end they're just numbers. Take it to the track and see how it performs. Specially the mph at the stripe.
At the end they're just numbers. Take it to the track and see how it performs. Specially the mph at the stripe.
Thread Starter
Intermediate
Joined: Apr 2014
Posts: 45
Likes: 0
